Most trees are naturally strong, long-lived plants. Occasionally, they suffer life-threatening damage from wind, snow, ice or hailstorms, resulting in broken branches, split crotches and trunks. Repairing a storm damaged tree involves several issues, with safety being paramount. If the trunk is split so that very little wood is left on one side, don't try to save it. If the trunk diameter is less than 15 inches and it's evenly split, give it a try.
Put on gloves, a hard hat and safety glasses to protect yourself. Focus your attention on the task in front of you, always keeping safety first.
Hook the top pulley of your block and tackle over a horizontal limb above the split on the strongest side of the tree. Pull on the rope to lift the split sides of the trunk together. Lash it tight with a square knot near the top of the split with an extra length of rope to hold it while you drill.
Mentally divide the length of the split in thirds. Drill through both sides of the split at the first and second third marks, using a 1/2 inch diameter drill bit.
Insert the bolts through the holes. Secure both ends with washers and nuts, screwing them down tight. Remove the block and tackle, but leave the lash at the top of the split for security.
Watch the tree over the next several months for signs of healing. Remove the lash at the top after six months. If the tree wilts significantly and does not leaf the following year, the tree must be cut down.
Enlist the help of a helper if you're trying to repair a large-diameter split.
Don't attempt to repair the split trunk of mature trees, especially the soft, brittle silver maple. The risk of property damage and personal injury outweighs the value of saving these trees.